The term Bullet Camera comes from
its resemblance to a rifle bullet. Generally long and
tapered like a cylinder, it looks like an oversized ammo
cartridge.

Most bullet cameras come with a fixed
4mm lens that allows a 70 degree angle of view. This is
the widest angle you can have without distorting the
picture. A 4mm lens will allow you to see facial
features out to about 35 feet. If infrared is included
you can generally see 35 feet minimum with no external
lighting, some can see up to 70 feet. Some devices
capture images in color which is best for daytime
lighting. For nighttime viewing choosing an infrared
camera, which captures images in black and white is
better. Many of the products will display color during
the day and automatically switch to black and white
infrared viewing when light levels are low.